U.S. Pat. No. 6,693,247 B1 describes an on-load tap changer which functions according to the reactor switching principle. The on-load tap changer includes a base plate and a top plate, between which a motor, a transmission and the contact device are arranged. The fixed contacts are arranged circularly on the base plate and are connected by different contact units, which are actuated by way of the transmission. Contacting of the fixed contacts with the winding taps takes place on the rear side of the base plate. The transmission is fixed substantially to the top plate, which consists of steel.